Winder shaft assembly



June 8, 1965 s. T. oRToN, JR 3,188,017

WINDER SHAFT AS SEMBLY Filed Aug. 5, 1963 2 Sheets-Sheet l I ATTORNEYS June 8, 1955 s. T. oR'roN, JR

V WINDER SHAFT ASSEMBLY 2 Sheets-Sheet 2 Filed Aug. 5, 1963 n .el

INVENTOR. SAMUEL T. ORTON, JR. BYwa/'M m ATTOBLIEYS United States Patent O 3,188,017 WENBER SHAFT ASSEMBLY Samuel T. Orton, Jr., Lunenburg, Mass., .assigner to @rtm1 Corporation, a corporation of Massachusetts Filed Aug. 5, 1963, Ser. No. 299,748 Claims. (Cl. 242-72) This invention relates to an improved Winder shaft assembly of a type Which is useful for internally gripping and rotatably supporting an annular core for Winding a length of paper, fabric, or the like thereabout. The invention is more particularly concerned With Winder shafts of the type having a plurality of locking lugs or pins Which are projectable radially outwardly from the surface of the shaft to internally grip a sheet Winding core.

The development of Winder shafts of this general type has extended over a long period, and has principally been concerned With resolving two basic problems. First, it is desirable to provide `a maximum of transverse stiffness for supporting the core against sagging, but at the same time to reduce the shaft Weight to a minimum. The rolls of sheeting to be Wound are characteristically quite long and heavy; for example, a roll of paper of 36 inch diameter and 90 inch Width Wound on a pasteboard core of 3 inch inside diameter, may Weigh about 1600 pounds. The shaft must therefore be quite stiff to prevent sagging to an extent which Would produce uneven tension in the Winding roll. However, the Winder shafts are handled manually, being removed and replaced at frequent intervals for each successive Winding operation, and so a minimum of Weight is desirable to avoid fatigue of Workers and consequent hazards to safety. Secondly, some means must be provided for extending and retracting the locking lugs, which are distributed over the considerable face length of the Winder shaft, .and if such means are susceptible to relatively rapid Wear or damage, the difficulty, expense, and loss of productive time entailed in repairing the shafts becomes severe. Previously proposed constructions have generally been both susceptible to damage and quite difficult to repair, requiring disassembly for the purpose.

An early form of Winder shaft is described in U.S. Patent No. 1,192,063, issued to Frank H. Hoberg, on July 25, 1916. In this construction, a series of locking lugs are actuated by cam means formed in a longitudinally-slidable rod. These means are susceptible to very rapid Wear because of the very high contact pressures on the cam surfaces, elastic distortion of the cam rod, and the application of vectorial forces through the lugs, causing rapid Wear of their guides. There is also extreme difficulty in achieving and maintaining uniform protrusion of the lugs, with the result that the sheet Winding core might be distorted into ovality or become longitudinally Warped by the Winder shaft. Furthermore, the transverse stiffnessof this construction Was not great in relation to its Weight, since the mechanical apparatus for extending the lugs afforded no contribution to the stiliness of the shaft assembly.

Later developments have tended in the direction of actuating the locking lugs pneumatically or hydraulically. Mandrels for Winding coils of short Widths became known, in which cylinders Were radially drilled in longitudinally-spaced relation in a solid shaft, and joined by a longitudinal bore to supply pressure fluid to them; the locking lugs Were used as pistons slidably received in the cylinders for extension by the fluid. Such a mandrel is shown, for example, in U.S. Patent No. 2,321,146 to Jones. However, constructions of this kind are not feasible for use in Winding rolls of very large Widths, because of the high ratio of Weight to transverse stiffness.

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Furthermore, if one cylinder became Worn, the entire shaft had to be replaced.

It is desirable to use compressed air rather than hydraulic fluid, because of leakage problems associated with the latter. However, the high moisture content of compressed air found in many industrial plants can produce a great deal of corrosion in the cylinders, With eventual failure. In a solid shaft construction, the cylinders cannot be individually replaced, and failure of .any one requires replacement of the entire shaft.

The majority of Winder shafts now in use utilize a comparatively light but stiff cylindrical tube as the shaft member, and do not attempt to provide cylinders for actuating the locking lugs, but rather employ an elastic inner tube which is received Within the shaft and inflated to cause extension of the locking lugs. The elastic tube may be a single tube extending the full length of the shaft, or a series of short axially-spaced tubes. However, this arrangement creates an inherent weakness, since a leak Will make the shaft completely inoperative. The movement of the locking lugs radially inwardly and outwardly tends to cause fairly rapid Wear of these tubes, even When the lugs are mounted on segmented leaves about the tubes, so that replacement is a frequent problem. Furthermore, repair of the tube or lugs requires dismantling of the shaft assembly, including the removal of end plugs provided to furnish bearing means and to contain a valve assembly for inflating the inner tube. If a single tube extends the full length of the shaft, it is not feasible to provide transverse stiffening Within the shaft; but if shorter tubes are positioned between intervening transverse supports, disassembly for repair becomes even more complex.

It is the primary object of the present invention to provide a Winder shaft assembly having an improved ratio of transverse stiffness to Weight. It is a further object to provide an improved Winder shaft assembly Which is less subject to disabling wear, and in Which those parts which are relatively susceptible to Wear may be individually replaced Without requiring dismantling of the entire shaft assembly. It is still a further object of the invention to provide a Winder shaft assembly of a type having pneumatically-extensible locking lugs, with improved cylinder-forming and transverse stiifening means. It is another object to provide such a Winder shaft With improved means for releasing and admitting compressed air to the cylinders, which means exhibits improved resistance to accidental damage by necessary manual handling. Further objects and advantages of the invention Will appear as the following description proceeds.

In general, I carry out the invention according to a preferred embodiment thereof, by placing a plurality of stiffening strut means in axially-spaced relation internally of a tubular Winder shaft; and the strut means also form internal cylinders for slidably receiving a series of locking pistons, of which the outer ends comprise lug p0rtions for projection outwardly of the shaft to engage a Winding core. Preferred forms of this construction permit removal and replacement of cylinder-forming elements of the strut means through the shaft Wall, Without dismantling the assembly through the end of the tubular shaft. The strut means engage portions of the internal surface of the shaft tube for transverse support thereof, and thus perform a dual function, of affording expansible chambers for actuation of the locking lugs, and at the same time of stifening the shaft transversely. An improved stitfness-to-Weight ratio results.

In one form, each strut means comprises a cylindrical tube which extends radially of the shaft axis, and a pair o-f plugs extending through lthe shaft Wall to engage and secure the tube. In this form, successive tubes may be angularly displaced from one another, for example at 90 degrees, to form cross-bracing for the shaft. Such tubes also conveniently form the cylinders for the locking lugs, since they may be individually removed and replaced through the plug opening in the shaft if worn, without dismantling the assembly. Alternatively, cruciform, Y- form, or other tubing elements may be used, each leg of the tubing element rproviding a cylinder for a locking lug. In these forms, the cylinders are preferably formed in the plugs for convenient replaceability. In either case, the plug means may be tapered and adjustably engaged with the tubing, so as to place it under preloading in tension or compression, and thereby further contribute to the stiffness of the assembly.

In another form, the strut means may include a series of spools each having a web portion for receiving the plugs, and annular flanges extending axially from the web portion about its periphery, the whole spool forming a unitary peripheral surface closely engaging the internal surface of the shaft to provide support at all points. The cylinders in this case are preferably formed in the plugs for replaccability through the plug openings, and the plugs are threaded in radial bores formed in the spool after it is seated in the shaft. A series of such strut means axially abutting one another transversely stiffens the shaft over its entire lengt-h, but entails a relatively small yweight penalty. The web portion may be in the form of a circumferentially-continuous disc, or may be provided with lightening holes spaced circumferentially intermediate each cylinder to further reduce the total weight without materially increasing the flexibility of the shaft.

The strut means may be formed of different materials than the shaft tube, with several attendant advantages. In particular, it is desirable that the shaft tube be made of steel or other material having a high modulus of elasticity for maximum stiffness, While the stru-t means may be formed of aluminum or other rather relatively lightweight but relatively low modulus materials, which are adequately strong in compression, The strength-to-weight ratio is thereby further improved. Additionally, the shaft will normally be made of stock tubing having some tolerance as to internal dimensions and ovality, and strut means of some relatively soft material such as aluminum may be readily forced into exact conformity with the internal surface of such tubing by driving the strut means in with a force t; any excess material will be smeared away from the strut. This feature is of particular signiticance in an embodiment incorporating spools in the strut means.

As a further feature of the invention, I provide improved valve means for selectively admitting and releasing compressed air to and from the expansible chamber defined interiorly of the shaft. Conventionelly, a check valve having a protruding valve stem is mounted in the axial end of the shaft, so that the expansible chamber may be illed with compressed air by applying an air nozzle to the stem, and subsequently released by manually depressing the valve stem. However, it commonly occurs in practice that the air nozzle is carelessly applied to the Valve stem, causing deformation which interferes with its operation and requires frequent replacement. To overcome this maintenance difficulty, I provide a branched passage including an inlet having a stemless check valve, leading to the expansible chamber, and an outlet port having a separate manually-operable release valve to relieve the pressure in the expansible chamber when it is desired to remove the shaft from the core. Consequently, application of an air nozzle to the inlet valve can produce no mechanical dam-age to this valve or to the release valve.

While the specification concludes with claims particularly pointing out the subject matter which I re-gard as my invention, it is believed that a clearer understanding may be gained from the following detailed description of preferred embodiments thereof, referring to the accompanying drawings, in which:

FIG. 1 is a fragmentary view in sectional elevation of a first embodiment of they invention;I

FIG. 2 is a sectional View taken along line 21-2 in FIG. l, looking in the direction of the arrows;

FIG. 3 is a fragmentary View in sectional eleva-tion of a modified form of Winder shaft; and

FIG. 4 is a sectional View taken along line fri-4 in FIG. 3, looking in the direction of the arrows.

A first form of the improved Winder shaft assembly is shown in FIGS. l and 2, and includes a tubular cylindrical shaft lll, which is preferably of steel, magnesium alloy, or or other material having a high strength-toweight rat-io. It will be understood that the shaft is intended to be inserted in a conventional manner within an annular winding core (not shown) for internal gripping thereof, and the diameter of the shaft may be selected accordingly, The core diameter is selected with reference to the particular sheet m-aterial to be wound, and is usually of the minimum diameter which will not produce an injuriously sharp curling of the material as it initially winds about the core. A steel support l2 is slidably received in each end of the shaft to enclose the assembly and provide bearing support means. Gudgeon portions l5 of the supports are removably received with a tight ft in the internal surface .14 of the shaft, and the supports extend into plain journals 16 in the embodiment shown, although it will be apparent that anti-friction bearings may be utilized if desired.

A series of locking pistons 18 are provided, each having a 4lug portion 2i) for selective extension outwardly of the periphery of the shaft to an extended position shown in dotted lines, for gripping the internal surface of the Winding core. The pistons are slidably received and guided in cylinders 22 formed in tapered threaded plugs 24, which cooperate with a series of axially-spaced spools 26 to form strut means in the assembly.

Each of .the spools 26 includes a web portion 28, which in the form shown is circumferentially continuous, but may be interrupted by lightening holes intervening between the portions receiving the plugs 24. The web portion is peripherally extended to form axial annular frange portions 30, the entire spool providing a cylindrical peripheral surface 32 for closely engaging the internal surface 14 of the shaft.

A series of the spools are first inserted in the tube from the ends, axially .abutting one another and the supports l2 at the ends of the shaft, to provide continuous internal support. Each spool is formed with an axial bore 32 extending therethrough, to connect all of the internal spaces f the assembly into a single expansib'le chamber cornmunicating with the faces of each piston lil. It is preferred that the spools be made of some relatively soft Inaterial such as aluminum, so that they may be forced into the interior of the shaft even though its surface may not be perfectly circular or of uniform diameter. As the spools are forced into place, excess material Will be smeared away from their surfaces, thus insuring a fully conforming fit with the interior of the shaft, and consequently a maximum of support.

The web portions 28 of the spools lare bored radially as at 34, and this is preferably done after the spools are inserted in the axle, so that the bore passes in true alignment through the shaft and the spool. In the form shown, `four pistons 1S are provided in each spool at 90 degree spacings, but any greater or lesser number may be used if desired. The bores 34 are then threaded at 36 for engagement with the threads of the plugs 24, Iand countersunk through the shaft to receive a tapered por-tion 3S of each plug, which serves to seal the assembly positively.

In their initial form, the plugs are flat headed, as suggested in dotted lines at liti, having screwdriver slots 4,2 for threading into the tapped bores of the spools. Following assembly, the projecting portions lof the plugs are ground away to conform smoothly to the circular contour of the shaft. l prefer to preload the assembly by tightly threading the plugs, thus applying tension transversely of the shaft to the spool, Which is effective to increase the transverse stiffness of the assembly against deflection by an applied load.

The pistons i8 are retained in place by split retaining rings d4, and provided with resilient compression rings 46. A coil spring 48 is interposed in each cylinder to return the locking lug to the retracted position shown in solid lines when the air pressure is released from the shaft. To assist in guiding the reciprocatory movement of the pistons, the lug portions are received through mating openings 50 in the heads of the plugs.

lTo supply the interior of the assembly with compressed air for extending the lugs 20, the support i12 is formed with .a branched internal passageway 52, one branch of Which communicates with the exterior through a conventional one-Way check valve 54, Which is secured by a tapered insert 56 threaded thereon and preferably formed of hardened steel to reduce accidental damage. Compressed air is supplied by means of a nozzle 5S, Whose conical tip is fitted int-o a mating recess 6d in the insert S6. A screen `filter 62 protects the assembly from the entry of dirt and dust. The valve 54 differs from conventional arrangements in that it is not provided With a valve stem for releasing the pressure lwhen it is desired to remove the supported core. Such stems are subject to damage by careless handling of the compressed air nozzle, requiring frequent maintenance and replacement. Instead, the branched passage 52 can be vented to the atmosphere through the periphery of the shaft 10, by mean-s of an exhaust port bushing 6d threaded in the shaft. A valve for closing the exhaust port is formed by a piston 66 having a stem 6d slidably received in the bushing, and provided With a resilient compression ring 70.

Application -of the compressed air nozzle 58 to the insert 56 supplies air to the interior of the shaft assembly, `and forces the piston 65 outwardly to the position shown to block the outlet port. To release the air pressure, it is merely necessary to manually depress the :stem 68 to drive the pist-on past the opening of the passage 52 into an extended recess 72 slidably receiving the piston, thereby communicating the exhaust port with the interior of the assembly.

A `modified embodiment of the Winder shaft is shown in FIGS. 3 and 4, in which elements similar to those of the foregoing embodiment are similarly numbered, with prime superscripts. In this form, each of the strut means cornprises a cylindrical tube titl, and a pair of plugs 24 threaded in diametrically-opposed relation in threaded openings 82 in the shaft lll', to engage the tube Si) in compression. Each plug has a cylindrical flange portion 34 of reduced diameter received Within an end of the tube to form a columnar assembly ltherewith. The columns may be prestressed in compression to increase the transverse rigidity of the assembly. Al-ternatively, the plugs may be threadedly engaged in the tubes, so that prestressing in tension could be obtained. The interior surfaces of the tubes Si) form the cylinders slidably receiving the pistons i8.

Stili further increase in rigidity can be secured by lling the void spaces yWithin the assembly with a foamed plastic filling 36, and for this purpose, the various tubes are interconnected by means of a longitudinal air conduit 88, communicating an air Valve 90 With the various pistons through the inlet -conduit 52. Before assembly, it is preferred to place the various tubes Si? along the conduit 88, in alignment with a series of ports 92, the tubes having diametral openings 94 for passage of the conduit therethrough. The yassembly of tubes with the conduit is then inserted axially into the shaft iti', and the plugs 24" are threaded through thetube wall into the ends `of the tubes, which may be readily aligned by manipulation through the shaft openings 32 `for this purpose. Finally, the plastic 6 filling 86 may be -foamed in situ, by depositing suitable reactants through the open ends of the shaft prior to fitting the supports therein;

In the preferred form, axially-adjacent tubes are angularly displaced about the axis of the shaft at 90 Iangles to one another, affording an effective cross-bracing. Alternatively, cruciform, Y-form or other shapes of tubing having various numbers of legs may be used, and some or all of the legs maybe used a-s cylinders for locking pistons.

While the arrangement shown provides plastic filling as a stiffening reinforcement, it requires complete disassembly of the shaft for replacement of individual tubes as their interior Walls become Worn. In an alternative form, the conduit 88 may be omitted, together with the plastic filling, so that the entire void space interior to the assembly forms a single chamber communicating the interior of each tube 8d with the air inlet through the openings 94. in this form, individual tubes dit may be replaced simply by unscrewing one of the support-ing plugs 24', and removing the -tube radially through the shaft opening 82. This arrangement Would consequently provide -considerable saving of maintenance expense and productive time, and -would be particularly desirable where corrosive conditions require frequent replacement of the cylinders.

While I have shown and described preferred embodiments of my invention by Way of illustration, it will be understood by those skilled in the art that various changes and modifications may be made therein Without departing from the true spirit and scope of the invention, which I therefore intend to define in the appended claims Without limitation to the details of the illustrated embodiments. In particular, the lugs need not directly engage a Winding core, but may expand a series of leaf segments circumferentially spaced about the shaft for coreless winding.

What I claim is:

1. A Winder shaft assembly for itnernally gripping and rotatably supporting a Winding core, comprising a cylindrical tubular shaft, a plurality of strut means received in axially-spaced diametrically-extending relation internally of said shaft in supporting engagement with the Walls thereof, said strut means forming internal cylinders extending transversely to the axis of said shaft said strut means being individually formed with bores communicating said cylinders in common through the interior of said tubular shaft, a plurality of locking pistons each slidably received in one of said cylinders to define, With said cylinders and said bores, a common expansible chamber interiorly of said tubular shaft, said locking pistons extending outwardly into lug portions, said shaft being formed with openings for projection of saidlug portions outwardly of said shaft into engagement with a Winding core received circumferentially about said shaft, and means for selectively admitting pressurized iiuid to said expansible chamber for projecting said lug portions.

2. A Winder shaft assembly as recited in claim 1, in which each of said strut means includes detachable plugs removably extending through the Walls of said shaft, said plugs each forming one of said cylinders interiorly thereof, whereby a Worn cylinder may be repaired by replacing individual plugs without dismantling the remainder of said assembly.

3. A Winder shaft assembly as recited in claim 1, in which each of said strut means comprises a cylindrical tube received transversely and interiorly of said shaft, and a pair of plugs received 1`n and engaging diametral portions of the Walls of said shaft and engaging said tube to support said diametral portions of said shaft against transverse displacement.

4. A Winder shaft assembly as recited in claim 3, each of said tubes forming at least one of Said cylinders 1n- .teriorly thereof.

5. A Winder shaft assembly as recited in claim 3, in which axially-adjacent ones of said tubes are angularly displaced relative to one another about the longitudinal axis of said shaft to provide cross-bracing of the assembly.

aisaoiv 6. A Winder shaft as recited in claim 3, in which said plugs are adjustably engaged in said diametral portions of said shaft for applying preloading to said tubes in directions transverse to said shaft.

7. A Winder shaft assembly as recited in claim ll, in which each of said strut means comprises an annular spool, each of said spools including a web portion and annular flanges extending in opposite directions axially of said shaft from said web portion for abutting and spacing axially-adjacent ones of said spools, said annular flanges and said web portion forming a common cylindrical peripheral surface internally engaging and supporting said shaft over substantially the full axial length of said spool.

3. A Winder shaft assembly as recited in claim 7, in which said spools are formed of a material having a lower strength in shear than the material of said shaft, whereby said peripheral surface of each spool is formed by its assembly into the shaft to conform with the interior surface thereof.

9. A Winder shaft assembly as recited in claim i, in which said means for selectively admitting pressurized fluid to said chamber comprises means received in an end of said shaft forming a branched conduit communicating with said chamber and terminating exteriorly in an inlet branch and an outlet branch, a one-Way check valve arranged in said inlet branch to admit pressurized fluid thereto, and a manually-operable release Valve arranged in said outlet branch to selectively release pressurized fluid from said chamber, said release valve being constructed and arranged for closure by fluid pressure in said inlet branch.

10. A Winder shaft assembly as recited in claim 9, in which said release valve comprises a piston slidably received in said outlet branch for manual displacement to a first position communicating said chamber with said outlet branch and closing said inlet branch, and for displacement by fluid pressure in said inlet branch to a second position closing said outlet branch and communicating said chamber with said inlet branch.

11. A Winder shaft assembly for internally gripping and rotatably supporting a winding core, comprising a cylindrical tubular shaft having a series of longitudinallyspaced openings therein, a plurality of strut means received in axially-spaced diametrically-extending relation internally of said shaft and having portions gripping said shaft about said openings for transversely stiifening the assembly, said strut means forming internal cylinders extending transversely to the axis of said shaft, said strut means being individually formed with bores communicating said cylinders in common through the interior of said tubular shaft, a plurality of locking pistons each slidably received in one of said cylinders to define, with said cylinders and said bores, a common expansible chamber interiorly of said tubular shaft, said locking pistons extending outwardly into lug portions, said lug portions being received through said openings for projection outwardly of said shaft into engagement with a winding core received circumferentially about said shaft, and means for selectively admitting compressed air to said expansible chamber for projecting said lug portions.

12. A Winder shaft assembly as recited in claim 11, in

which said gripping portions of said strut means form said cylinders interiorly thereof and are individually removable from the assembly through said openings for replacement.

13. A Winder shaft assembly as recited in claim 11, in which said gripping portions of said strut means are adjustably threaded in said openings for applying preloading to said strut means in directions transverse to said shaft.

M. In a Winder shaft assembly, for internally gripping and rotatably supporting a winding core, a cylindrical shaft formed with internal cylinders, a plurality of locking pistons slidably received in said cylinders to define a common expansible chamber therewith, said pistons extending outwardly into lug portions, said shaft being formed with openings for projection of said lug portions outwardly of said shaft into engagement with a winding core received circumferentially about said shaft, and means for selectively admitting and releasing compressed air to and from said chamber comprising means forming a branched passageway communicating with said chamber and terminating exteriorly in an inlet branch and an outlet branch, a one-way check valve arranged in said inlet branch for admitting compressed air to said chamber, and a piston slidably received in said outlet branch for manual displacement to a rst position closing said inlet branch and communicating said chamber with said outlet branch, and for displacement by air pressure in said inlet branch to a second position closing said outlet branch and communicating said chamber with said inlet branch.

1S. A Winder shaft assembly for internally gripping and rotatably supporting a winding core, comprising a cylindrical tubular shaft, a plurality of strut means received in axially spaced relation internally of said shaft, each of said strut means being formed with a cylindrical peripheral surface internally engaging and supporting said shaft, said strut means forming internal cylinders extending transversely to the axis of said shaft, said strut means further being formed with bores communicating said cylinders in common through the interior of said tubular shaft, a plurality of locking pistons each slidably received in one of said cylinders to define, with said cylinders and said bores, a common expansible chamber interiorly of said shaft, said `locking pistons extending outwardly into lug portions, said shaft being formed with openings for projection of said lug portions outwardly of said shaft into engagement with a winding core received circumferentially about said shaft, and means for selectively admitting compressed air to said expansible chamber for projecting said lug portions.

References Cited by the Examiner UNITED STATES PATENTS MERVIN STEIN, Primary Examiner. 

1. A WINDER SHAFT ASSEMBLY FOR ITNERNALLY GRIPPING AND ROTATABLY SUPPORTING A WINDING CORE, COMPRISING A CYLINDRICAL TUBULAR SHAFT, A PLURALITY OF STRUT MEANS RECEIVED IN AXIALLY-SPACED DIAMETRICALLY-EXTENDING RELATION INTERNALLY OF SAID SHAFT IN SUPPORTING ENGAGEMENT WITH THE WALLS THEREOF, SAID STRUT MEANS FORMING INTERNAL CYLINDERS EXTENDING TRANSVERSELY TO THE AXIS OF SAID SHAFT SAID STRUT MEANS BEING INDIVIDUALLY FORMED WITH BORES COMMUNICATING SAID CYLINDERS IN COMMON THROUGH THE INTERIOR OF SAID TUBULAR SHAFT, A PLURALITY OF LOCKING PISTONS EACH SLIDABLY RECEIVED IN ONE OF SAID CYLINDERS TO DEFINE, WITH SAID CYLINDERS AND SAID BORES, A COMMON EXPANSIBLE CHAMBER INTERIORLY OF SAID TUBULAR SHAFT, SAID LOCKING PISTONS EXTENDING OUTWARDLY INTO LUG PORTIONS, SAID SHAFT BEING FORMED WITH OPENINGS FOR PROJECTION OF SAID LUG PORTIONS OUTWARDLY OF SAID SHAFT INTO ENGAGEMENT WITH A WINDING CORE RECEIVED CIRCUMFERENTIALLY ABOUT SAID SHAFT, AND MEANS FOR SELECTIVELY ADMITTING PRESSURIZED FLUID TO SAID EXPANSIBLE CHAMBER FOR PROJECTING SAID LUG PORTIONS. 